Preparation method and application of acid-base controllable formaldehyde-yne carbonate catalyst

Abstract

The application discloses a formaldelhyde acetylene carbonate catalyst with controllable acid-base, which comprises a carbonate of Cu, a carbonate of Bi, a carbonate and hydroxide of Si, and a carbonate and hydroxide of Zr. The application also discloses a preparation method of the catalyst, specifically: Cu compound, Bi compound and Zr compound are dissolved in nitric acid, then Si compound and a precipitant are added to adjust the pH to alkaline, co-precipitation, standing, drying, sieving, and the catalyst is obtained. The catalyst can be used in the synthesis of 1,4-butynediol in a formaldelhyde acetylene reaction. The main components of the catalyst are carbonates of copper and bismuth, which contain carbon elements, so that the reaction active center CuC2 can be rapidly generated in the reaction process. Zr elements are added as carriers to increase the dispersity and adjust the acid-base of the adsorption sites on the surface of the catalyst, so that the reactants can more efficiently contact the catalyst, and thus the activation efficiency in the formaldelhyde acetylene reaction is higher.

Description

Technical Field

[0001] This invention belongs to the technical field of catalyst preparation methods, specifically relating to a method for preparing an acid-base controllable formaldehyde acetylation carbonate catalyst, and also relating to the application of this catalyst. Background Technology

[0002] 1,4-Butynediol is an important intermediate in organic synthesis, with significant applications in polymers, rubber, coatings, dyes, and pharmaceuticals. The acetylation of formaldehyde to prepare 1,4-butynediol is a crucial chemical synthesis method, involving the introduction of hydrogen gas to induce interaction between the carbonyl and methyl groups in the formaldehyde molecule, forming 1,4-butynediol. The reaction requires a catalyst under appropriate temperature and pressure. In the acetylation of formaldehyde to prepare 1,4-butynediol, the selection of the catalyst and the control of temperature and pressure have a significant impact on improving yield and selectivity. Simultaneously, the safety and environmental friendliness of the reaction must be considered, and appropriate measures must be taken to handle byproducts and waste. Most existing commercial Cu-Bi catalysts are prepared using co-precipitation and stepwise precipitation methods, requiring high-temperature calcination to generate copper bismuth oxide crystal structures. Furthermore, the copper oxide needs to be reduced during the reaction to activate it. Therefore, seeking a novel, efficient, and low-cost acetylation catalyst for formaldehyde is particularly important. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing an acid-base tunable formaldehyde acetylated carbonate catalyst, which greatly shortens the time required for catalyst activation and reaction, and reduces reaction costs.

[0004] Another object of the present invention is to provide the application of the above-mentioned acid-base tunable formaldehyde acetylation carbonate catalyst in the synthesis of 1,4-butynediol via formaldehyde acetylation reaction.

[0005] The technical solution adopted in this invention is a method for preparing an acid-base tunable formaldehyde acetylation carbonate catalyst, specifically as follows:

[0006] The compounds of Cu, Bi, and Zr were dissolved in nitric acid, and then the three solutions were mixed. The compound of Si was added to form a precursor mixture. A precipitant was added to adjust the pH of the solution to alkaline, and co-precipitation was performed. After standing, the resulting precipitate was dried, ground, and sieved to obtain the catalyst.

[0007] The invention is further characterized in that,

[0008] The compounds of Cu are copper nitrate and / or copper sulfate; the compounds of Bi are bismuth nitrate; the compounds of Zr are basic zirconium carbonate and / or zirconium dioxide; and the compounds of Si are sodium silicate.

[0009] In the precursor mixture, the molar ratio of Cu, Bi, Si and Zr elements is 1–100: 1–100: 0.1–5: 0.1–5.

[0010] The precipitant is any one or more of sodium hydroxide solution, sodium carbonate solution, and ammonia solution; the concentration of the precipitant is 0.3–10 mol·L⁻¹. -1 Furthermore, the pH of the solution is adjusted to 8-9 using a precipitant.

[0011] The co-precipitation temperature is 20–90℃, and the settling time is 10–20 h; the drying temperature is 40–150℃, and the drying time is 1–30 h; when sieving, a 100–200 mesh sieve is used.

[0012] Another technical solution adopted in this invention is the application of an acid-base controllable formaldehyde acetylation carbonate catalyst in the synthesis of 1,4-butynediol via formaldehyde acetylation reaction; specifically, the formaldehyde acetylation carbonate catalyst, formaldehyde aqueous solution, and sodium acetate are mixed, stirred and heated to 70-90°C, nitrogen gas is introduced for 10-30 min for purging, followed by the introduction of a mixture of acetylene and nitrogen gas, activation for 1-5 h, and then acetylation reaction for 5-15 h to finally obtain the product.

[0013] The beneficial effects of this invention are:

[0014] (1) Compared with the formaldehyde acetylation catalyst in the prior art, the catalyst of the present invention has no calcination process, and its active component exists directly as a Cu carbonate species. The catalyst preparation method is simple, and the catalyst preparation cost is greatly reduced while achieving the same 1,4-butynediol yield.

[0015] (2) The addition of zirconium makes the formaldehyde acetylation catalyst acid-base adjustable, greatly enriches the acid-base sites on the catalyst surface, promotes the conversion rate of basic copper carbonate to CuC2 during the activation process, and thus greatly shortens the overall reaction time and greatly reduces the reaction cost.

[0016] (3) The main components of the catalyst of the present invention are copper and bismuth carbonate species. The advantage of containing carbon elements makes it possible to generate the active reaction center CuC2 more quickly during the catalyst reaction process. The addition of Zr elements as a support further increases the dispersion of the Cu, Bi and Si system. On the other hand, it adjusts the acidity and alkalinity of the adsorption sites on the catalyst surface, so that the reactants can contact the catalyst more efficiently, thereby achieving higher activation efficiency in the formaldehyde acetylation reaction. It can quickly reach the activation requirements and start the reaction within 2 hours. Compared with commercial catalysts, its activation efficiency is improved by more than 70%. Attached Figure Description

[0017] Figure 1The XRD pattern of the catalyst prepared in Example 5 of this invention;

[0018] Figure 2 The NH3-TPD diagram shows the acidic site distribution of the catalyst prepared in Example 5 and the catalyst in Comparative Example 1.

[0019] Figure 3 The basic site distribution CO2-TPD diagrams of the catalyst prepared in Example 5 of this invention and the catalyst in Comparative Example 1 are shown. Detailed Implementation

[0020] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings.

[0021] The method for preparing the acid-base tunable formaldehyde acetylated carbonate catalyst of the present invention is as follows: Cu compound, Bi compound, and Zr compound are dissolved in nitric acid respectively, the three solutions are then mixed, Si compound is added to form a precursor mixture, a precipitant is added to adjust the pH of the solution to alkaline, co-precipitation is performed, the mixture is allowed to stand, the resulting precipitate is dried, ground and sieved to obtain the catalyst.

[0022] The compounds of Cu are copper nitrate (Cu(NO3)2·3H2O) and / or copper sulfate (CuSO4);

[0023] The compound of Bi is bismuth nitrate (Bi(NO3)3·xH2O);

[0024] The compounds of Zr are basic zirconium carbonate (CH2O7Zr2) and / or zirconium dioxide (ZrO2).

[0025] In the precursor mixture, the molar ratio of Cu, Bi, Si and Zr elements is 1–100: 1–100: 0.1–5: 0.1–5.

[0026] Preferably, the molar ratio of Cu, Bi, Si and Zr is 60:1:1:0.1 to 3;

[0027] The compound of Si is sodium silicate (Na2SiO3·9H2O);

[0028] The precipitant is any one or more of sodium hydroxide solution, sodium carbonate solution, and ammonia solution; the concentration of the precipitant is 0.3–10 mol·L⁻¹. -1 Preferably, the concentration of the precipitant is 3–5 mol·L⁻¹. -1 .

[0029] The pH of the solution is adjusted to 8-9 using a precipitant, and more preferably, the pH of the solution is adjusted to 8-8.5;

[0030] The coprecipitation temperature is 20–90℃, preferably 55–75℃.

[0031] The settling time is 10–20 hours; the drying temperature is 40–150℃, and the drying time is 1–30 hours.

[0032] When sieving, use a 100-200 mesh sieve;

[0033] The acid-base tunable formaldehyde acetylated carbonate catalyst of the present invention comprises the following components: Cu carbonate, Bi carbonate, Si carbonate and hydroxide, and Zr carbonate and hydroxide.

[0034] The carbonate of Cu is Cu(OH)2CO3. The carbonate of Bi is Bi2(CO3)O2. The carbonates and hydroxides of Si are one or more of H4SiO4, H2SiO3, and Si(CO3)2. The carbonates and hydroxides of Zr are Zr(OH)4 and CH2O7Zr2.

[0035] The formaldehyde acetylation carbonate catalyst prepared by the method of the present invention is used in the formaldehyde acetylation reaction to synthesize 1,4-butynediol. Specifically, the catalyst, formaldehyde aqueous solution and sodium acetate are mixed, stirred and heated to 70-90°C, nitrogen gas is introduced for 10-30 min for purging, and then a mixture of acetylene and nitrogen gas (C2H2 content is 65-70%, mixed gas flow rate is 80-85 mL / min) is introduced. After activation for 1-5 h, the acetylation reaction is carried out for 5-15 h to finally obtain the product.

[0036] The mass ratio of catalyst, formaldehyde aqueous solution, and sodium acetate is 4-6:20-30:0.5-2; the mass fraction of formaldehyde aqueous solution is 35-40%.

[0037] The Cu-Bi-Si-Zr catalyst prepared by the method of this invention has a crystal structure mainly consisting of carbonates corresponding to each element. This process greatly reduces the catalyst preparation cost, omits the calcination step and the copper oxide reduction process, and the controllability of acid and basic sites greatly shortens the time required for catalyst activation, thus significantly saving the catalyst preparation cost and the production cost of formaldehyde acetylation reaction.

[0038] Traditional catalysts, after high-temperature calcination, mainly consist of copper oxide (Cu) and bismuth oxide (Bi). During use, activation is required, a process involving the reaction of the catalyst with carbon (C) to form a CuC2 intermediate. This intermediate exhibits significant reactivity during catalysis. The unique feature of this invention's catalyst compared to traditional catalysts is that its carbonate species inherently contain carbon. This characteristic endows the catalyst with the ability to generate CuC2 reactive centers more rapidly during the reaction.

[0039] Carbonate species, as components of catalysts, provide a more rapid reaction pathway. During catalyst activation, carbonate species not only mediate the reaction but are also key components required for the formation of intermediates. Their carbon-containing structure provides favorable conditions for the formation of CuC2 intermediates, accelerating the generation of reactive centers.

[0040] In the catalytic reaction process, the CuC2 intermediate is considered a highly efficient active center, capable of promoting the reaction. The formation of this intermediate is closely related to the structure of the carbonate species, as the presence of carbon contributes to its formation and stability. Therefore, the catalyst of this invention, through the unique structure of its carbonate species, achieves faster and more efficient CuC2 intermediate formation, thereby improving catalytic activity and efficiency. This design concept provides new insights into catalyst applications, opening up new possibilities for process optimization and catalytic performance enhancement.

[0041] The following examples illustrate the process of formaldehyde acetylation reaction:

[0042] 5g of sieved catalyst particles were placed in a 100mL three-necked flask, and 75mL of 37% formaldehyde aqueous solution and 1g of sodium acetate were added. The solution was heated to 85℃ with stirring, and nitrogen gas was introduced for 10min for purging. Then, a mixture of acetylene and nitrogen gas (C2H2 content 70%, mixed gas flow rate 83mL / min) was introduced. After activation for 2 hours, the acetylation reaction was carried out for 7 hours. The reaction products were analyzed by gas chromatography for gas composition.

[0043] Example 1

[0044] In a 1L beaker, 100mL of water and 10mL of nitric acid were added. Under stirring, 0.1g of basic zirconium carbonate (CH2O7Zr2), 53.2g of Cu(NO3)2·3H2O, and 1.6g of Bi(NO3)·5H2O were added sequentially to prepare a metal ion solution. In a 1L plastic beaker, 63.6g of Na2CO3 and 0.38g of Na2SiO3 were dissolved in 200mL of water as precipitants. The metal ion solution and precipitant were subjected to a co-precipitation reaction. The solution was then dried and sieved at 60℃ for later use. A formaldehyde acetylation catalyst with a Cu:Bi:Si:Zr molar ratio of 60:1:1:0.1 was prepared for reaction activity investigation. In a three-necked flask, 5g of the sieved catalyst was placed, and formaldehyde aqueous solution and sodium acetate were added. The mixture was heated with stirring, activated by gas for 2 hours, and reacted for 7 hours. The resulting liquid product was collected, and its composition was analyzed by gas chromatography. The results showed that the formaldehyde conversion rate was 95.2% and the selectivity for 1,4-butynediol was 88.1%.

[0045] Example 2

[0046] In a 1L beaker, 100mL of water and 10mL of nitric acid were added. Under stirring, 0.2g of basic zirconium carbonate (CH2O7Zr2), 53.2g of Cu(NO3)2·3H2O, and 1.6g of Bi(NO3)3·5H2O were added sequentially to prepare a metal ion solution. In a 1L plastic beaker, 63.6g of Na2CO3 and 0.38g of Na2SiO3 were dissolved in 200mL of water as precipitants. The metal ion solution and precipitant were subjected to a co-precipitation reaction. The solution was then dried and sieved at 60℃ for later use. A formaldehyde acetylation catalyst with a Cu:Bi:Si:Zr molar ratio of 60:1:1:0.1 was prepared for reaction activity investigation. In a three-necked flask, 5g of the sieved catalyst was placed, and formaldehyde aqueous solution and sodium acetate were added. The mixture was heated with stirring, activated by gas for 2 hours, and reacted for 7 hours. The resulting liquid product was collected, and its composition was analyzed by gas chromatography. The results showed that the formaldehyde conversion rate was 96.7% and the selectivity of 1,4-butynediol was 93.3%.

[0047] Example 3

[0048] In a 1L beaker, 100mL of water and 10mL of nitric acid were added. Under stirring, 0.5g of basic zirconium carbonate (CH2O7Zr2), 53.2g of Cu(NO3)2·3H2O, and 1.6g of Bi(NO3)3·5H2O were added sequentially to prepare a metal ion solution. In a 1L plastic beaker, 63.6g of Na2CO3 and 0.38g of Na2SiO3 were dissolved in 200mL of water as precipitants. The metal ion solution and precipitant were subjected to a co-precipitation reaction. The solution was then dried and sieved at 60℃ for later use. A formaldehyde acetylation catalyst with a Cu:Bi:Si:Zr molar ratio of 60:1:1:0.1 was prepared for reaction activity investigation. In a three-necked flask, 5g of the sieved catalyst was placed, and formaldehyde aqueous solution and sodium acetate were added. The mixture was heated with stirring, activated by gas for 2 hours, and reacted for 7 hours. The resulting liquid product was collected, and its composition was analyzed by gas chromatography. The results showed that the formaldehyde conversion rate was 97.9% and the selectivity of 1,4-butynediol was 97.3%.

[0049] Example 4

[0050] In a 1L beaker, 100mL of water and 10mL of nitric acid were added. Under stirring, 0.7g of basic zirconium carbonate (CH2O7Zr2), 53.2g of Cu(NO3)2·3H2O, and 1.6g of Bi(NO3)3·5H2O were added sequentially to prepare a metal ion solution. In a 1L plastic beaker, 63.6g of Na2CO3 and 0.38g of Na2SiO3 were dissolved in 200mL of water as precipitants. The metal ion solution and precipitant were subjected to a co-precipitation reaction. The solution was then dried and sieved at 60℃ for later use. A formaldehyde acetylation catalyst with a Cu:Bi:Si:Zr molar ratio of 60:1:1:0.1 was prepared for reaction activity investigation. In a three-necked flask, 5g of the sieved catalyst was placed, and formaldehyde aqueous solution and sodium acetate were added. The mixture was heated with stirring, activated by gas for 2 hours, and reacted for 7 hours. The resulting liquid product was collected, and its composition was analyzed by gas chromatography. The results showed that the formaldehyde conversion rate was 99.2% and the selectivity of 1,4-butynediol was 94.1%.

[0051] Example 5

[0052] In a 1L beaker, 100mL of water and 10mL of nitric acid were added. Under stirring, 1g of basic zirconium carbonate (CH2O7Zr2), 53.2g of Cu(NO3)2·3H2O, and 1.6g of Bi(NO3)3·5H2O were added sequentially to prepare a metal ion solution. In a 1L plastic beaker, 63.6g of Na2CO3 and 0.38g of Na2SiO3 were dissolved in 200mL of water as precipitants. The metal ion solution and precipitant were subjected to a co-precipitation reaction. The solution was then dried and sieved at 60℃ for later use. A formaldehyde acetylation catalyst with a Cu:Bi:Si:Zr molar ratio of 60:1:1:0.1 was prepared for reaction activity investigation. In a three-necked flask, 5g of the sieved catalyst was placed, and formaldehyde aqueous solution and sodium acetate were added. The mixture was heated with stirring, activated by gas for 2 hours, and reacted for 7 hours. The resulting liquid product was collected, and its composition was analyzed by gas chromatography. The results showed that the formaldehyde conversion rate was 95.1% and the selectivity for 1,4-butynediol was 82.1%.

[0053] Comparative Example 1

[0054] A commercial copper-bismuth-magnesium-silicon formaldehyde acetylation catalyst was sieved and its reactivity was investigated. 5g of the sieved catalyst was placed in a three-necked flask, followed by the addition of formaldehyde aqueous solution and sodium acetate. The mixture was heated with stirring, activated by gas purging for 2 hours, and reacted for 7 hours. The resulting liquid product was collected, and its composition was analyzed by gas chromatography. The results showed a formaldehyde conversion rate of 89.3% and a 1,4-butynediol selectivity of 91.1%.

[0055] The Cu-Bi-Si-Zr carbonate species catalyst prepared in Example 3 was characterized by X-ray diffraction, and the results were as follows: Figure 1The XRD patterns shown indicate that the main crystalline forms of the Cu-Bi-Si-Zr catalyst are Cu and Bi carbonate species Cu2(OH)2CO3 and Bi2(CO3)O2. According to existing literature, these are the main active components of the Cu-Bi series catalysts. The presence of carbon in the catalyst allows for more rapid formation of the active center CuC2 during the reaction, thus accelerating the catalyst activation process. The Si and Zr supports likely exist primarily in amorphous forms, which provides good dispersion for the active components. The catalysts in Example 5 and Comparative Example 1 were characterized for acid-base sites. Both catalysts were pretreated in an argon atmosphere at 400°C for 2 hours, and then adsorption-desorption experiments were conducted using the corresponding acid-base gases to obtain the corresponding acid-base site data. Figure 2-3 As shown, the results indicate that the addition of Zr support greatly enriches the acidic and basic sites on the catalyst surface, increases the number and intensity of acidic sites, and increases the number of adsorption sites for reactants, making them easier to be adsorbed and converted. The increase in basic sites promotes the rate of conversion of basic copper carbonate to CuC2 during the activation process, shortening the activation process and thus greatly reducing the overall reaction time and significantly lowering the reaction cost.

Claims

1. Acid-base tunable formonitrile carbonate catalysts, characterized in that, It comprises the following components: Cu carbonate, Bi carbonate, Si carbonate and hydroxide, and Zr carbonate and hydroxide; wherein the Cu carbonate is Cu(OH)2CO3; the Bi carbonate is Bi2(CO3)O2; the Si carbonate and hydroxide is one or more of H4SiO4, H2SiO3, and Si(CO3)2; and the Zr carbonate and hydroxide is Zr(OH)4 and CH2O7Zr2. The main components of the catalyst are copper and bismuth carbonate species. The presence of carbon in the catalyst allows for the more rapid generation of reactive centers CuC2 during the reaction process. The addition of Zr as a support further increases the dispersion of the Cu, Bi, and Si system. On the other hand, it adjusts the acidity and alkalinity of the adsorption sites on the catalyst surface, allowing the reactants to contact the catalyst more efficiently, thus resulting in higher activation efficiency in the formaldehyde acetylation reaction.

2. The method for preparing an acid-base tunable formaldiglycosyl carbonate catalyst according to claim 1, wherein, Specifically: The compounds of Cu, Bi, and Zr were dissolved in nitric acid, and then the three solutions were mixed. The compound of Si was added to form a precursor mixture. A precipitant was added to adjust the pH of the solution to alkaline, and co-precipitation was performed. After standing, the precipitate was dried, ground, and sieved to obtain the catalyst. The compound of Cu is copper nitrate and / or copper sulfate; the compound of Bi is bismuth nitrate; the compound of Zr is basic zirconium carbonate and / or zirconium dioxide; and the compound of Si is sodium silicate. In the precursor mixture, the molar ratio of Cu, Bi, Si and Zr is 1~100:1~100:0.1~5:0.1~5.

3. The method for preparing the acid-base tunable formaldehyde acetylation carbonate catalyst as described in claim 2, characterized in that, The precipitant is any one or more of a sodium hydroxide solution, a sodium carbonate solution, and an aqueous ammonia solution; the concentration of the precipitant is 0.3-10 mol L -1 ; and the pH of the solution is adjusted to 8-9 using a precipitant.

4. The method for preparing the acid-base tunable formaldehyde acetylation carbonate catalyst as described in claim 2, characterized in that, The co-precipitation temperature is 20~90℃, and the settling time is 10~20h; the drying temperature is 40~150℃, and the drying time is 1~30h; when sieving, a 100-200 mesh sieve is used.

5. The application of the acid-base tunable formaldehyde acetylation carbonate catalyst as described in claim 2 in the synthesis of 1,4-butynediol via formaldehyde acetylation reaction.

6. The application as described in claim 5, characterized in that, Specifically, the process involves mixing formaldehyde acetylation carbonate catalyst, formaldehyde aqueous solution, and sodium acetate, stirring and heating to 70-90℃, purging with nitrogen for 10-30 minutes, then introducing a mixture of acetylene and nitrogen gas for 1-5 hours of activation, followed by an acetylation reaction for 5-15 hours to finally obtain the product.

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